Aerial view of the Sunspot Solar Observatory site on Sacramento Peak in New Mexico. Sunspot will re-open Monday (Sept. 17) after having been closed for 10 days while authorities investigated criminal activity.

Credit: National Solar Observatory/NSF

It wasn't aliens, or a doomsday solar flare.

No, the Sunspot Solar Observatory — a National Solar Observatory facility high up on New Mexico's Sacramento Peak — has been closed for the past 10 days because of a criminal investigation.

"AURA has been cooperating with an ongoing law enforcement investigation of criminal activity that occurred at Sacramento Peak," representatives of the Association of Universities for Research in Astronomy, which operates Sunspot, wrote in a statement Sunday (Sept. 16). "During this time, we became concerned that a suspect in the investigation potentially posed a threat to the safety of local staff and residents. For this reason, AURA temporarily vacated the facility and ceased science activities at this location."

But things are about to get back to normal.

"In light of recent developments in the investigation, we have determined there is no risk to staff, and Sunspot Solar Observatory is transitioning back to regular operations as of September 17th," the statement added.

AURA officials had previously cited a "security issue" as the cause of the closure (which also affected a nearby post office) but did not elaborate. The FBI was apparently involved but kept pretty much everyone, including local law enforcement, in the dark about what was going on.

As often happens, rumors rushed in to fill the information-free void. Speculation ranged from the ridiculous (that the government wanted to squash news of an alien-life detection or civilization-destroying solar flare) to the plausible (that some bad actor had planted spy gear on the Sunspot grounds, which provide a good view of the White Sands Missile Range and Holloman Air Force Base).

That latter explanation may still be in play; AURA has not disclosed the nature of the criminal activity being investigated.

"We recognize that the lack of communications while the facility was vacated was concerning and frustrating for some," Sunday's AURA statement added. "However, our desire to provide additional information had to be balanced against the risk that, if spread at the time, the news would alert the suspect and impede the law enforcement investigation. That was a risk we could not take."

The Sunspot Solar Observatory was established in 1947. Its main eye on the sky today is the Dunn Solar Telescope, which was completed in 1969 and helps researchers better understand the sun, solar activity and its effects on Earth.

Nine people, from New Mexico State University and AURA, work at the observatory, AURA representatives said.

Michael was a science writer for the Idaho National Laboratory and has been an intern at Wired.com, The Salinas Californian newspaper, and the SLAC National Accelerator Laboratory. He has also worked as a herpetologist and wildlife biologist. He has a Ph.D. in evolutionary biology from the University of Sydney, Australia, a bachelor's degree from the University of Arizona, and a graduate certificate in science writing from the University of California, Santa Cruz. To find out what his latest project is, you can follow Mike on Google+.